It is known that many internal combustion engines, including positive-ignition engines (e.g., gasoline engines), are usually provided with a particle filter for collecting particulate matter (soot) generated by the engine, to lower pollutant emissions.
The soot that accumulated inside of the particle filter is removed from time to time in a soot combustion process, which is generally referred to as regeneration (e.g., active regeneration or passive regeneration), that occurs when the temperature of the particle filter exceeds a specific value (e.g., 500° C.) and sufficient oxygen is present in the exhaust gases. The known strategies for controlling particle filter regeneration are based on measurements of the pressure difference in the particle filter and/or mathematical models configured to provide a soot load estimate based on several different operating parameters.
However, there exists a need to improve the control of particle filter regeneration, and to precisely determine whether the particle filter is completely free of soot, for example at the end of a regeneration process, and to adjust and correct the estimated soot load and/or ash that accumulates in the particle filter over its service life.